The ominous warning said the safety of the embassies cannot be guaranteed after April 10. U.S. officials also confirmed North Korea loaded two missiles onto mobile launchers, making it seem more likely than ever that the country's rogue leader intends to launch a missile test in the next few days.
The growing tension is also rattling businesses. General Motors says it's making contingency plans for the safety of its employees if conditions deteriorate.
All of this comes after the Pentagon changed course as the U.S. tries to defuse the alarming situation with North Korea.
U.S. officials say they'll cut back on publicity for military drills taking place near North Korea.
The U.S. had promoted a parade of military might including showing off B-2 stealth bombers, F- 22 fighters and naval missile defenses. Now, they're going for lower profile.
North Korea moved a missile launcher to its east coast, a sign of a planned test-fire or a pre-emptive strike.
The missile could hit U.S. bases in Okinawa and Guam, where thousands of Americans live.
"I think we need to be careful to try and give Kim Jong Un an incentive to walk back from this brink, even as we also show firmness in our response," said Michael O'Hanlon, a foreign policy expert.
U.S. officials believe the North Korean leader won't pull the trigger on an attack. The North has never tested its new mobile missile.
Still, the U.S. and Japan say their missile interceptors are ready to go.
Friday, Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, said in an interview that North Korea's bellicose rhetoric and threats fit a decades-long pattern of provocation followed by uneasy peace.
"I wouldn't say I see anything to lead me to believe that this is a different kind of cycle," Dempsey said.
His remarks suggested that he does not believe the situation is headed toward war, despite a series of threatening statements by the North, including a declaration this week that its military is authorized to launch a nuclear attack on the United States.
The Associated Press contributed to this report.